28.11. Push notifications in Flutter with Firebase: Integration with external services

Push notifications are one of the most effective tools for engaging users in mobile apps. In Flutter, one of the most efficient ways to implement push notifications is by using Firebase Cloud Messaging (FCM), a free service offered by Google that allows sending notifications to Android and iOS devices. In this chapter, we'll explore how to integrate push notifications into your Flutter app using Firebase.

Firebase Configuration

Before you start, you need to configure Firebase for your Flutter project. To do this, go to the Firebase console and create a new project. After that, you need to add an Android or iOS app to your Firebase project. During this process, you will be asked for your app's Bundle ID, which can be found in the AndroidManifest.xml file for Android apps or the Info.plist file for iOS apps.

Adding dependencies

After setting up Firebase, you need to add the necessary dependencies to your Flutter project. To do this, add the following lines to your pubspec.yaml file:

dependencies:
  flutter:
    sdk: flutter
  firebase_core: ^0.5.0
  firebase_messaging: ^7.0.0

After adding these dependencies, run the 'flutter pub get' command to install the packages.

Firebase Messaging Configuration

After installing the dependencies, you need to configure Firebase Messaging in your application. First, you need to initialize Firebase in your app. To do this, add the following line of code to your application's main method:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

After that, you need to create a Firebase Messaging instance and request permission to send notifications. You can do this by adding the following code to your main widget's initState method:

@override
void initState() {
  super.initState();
  FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
  _firebaseMessaging.requestNotificationPermissions();
}

Receiving Push Notifications

To receive push notifications, you need to configure notification listeners. You can do this by adding the following code to your main widget's initState method:

_firebaseMessaging.configure(
  onMessage: (Map message) async {
    print("onMessage: $message");
  },
  onLaunch: (Map message) async {
    print("onLaunch: $message");
  },
  onResume: (Map message) async {
    print("onResume: $message");
  },
);

These listeners will be called when a notification is received while the app is running, when a notification is clicked by the user, or when a notification is received while the app is in the background, respectively.

Sending Push Notifications

To send push notifications, you can use the Firebase Cloud Messaging API or the Firebase console. In the Firebase console, you can send notifications to all users, user segments, or individual users. To send notifications through the API, you need to use the device's registration token, which can be obtained using the following code:

_firebaseMessaging.getToken().then((String token) {
  assert(token != null);
  print("Push Messaging token: $token");
});

Once you get the registration token, you can use it to send notifications to the specific device.

Conclusion

In this chapter, we explored how to implement push notifications in Flutter apps using Firebase Cloud Messaging. Implementing push notifications can significantly increase user engagement with your app, making it more valuable to your users and your business.